Method and system for determining quenching machining allowance of 42CrMo steel nitrided part

Abstract

The invention relates to a 42CrMo steel nitriding part quenching machining allowance determination method and system, and relates to the field of metal nitriding treatment.The 42CrMo steel nitriding part quenching machining allowance determination method comprises the steps that a split image of a split face of a part is collected; analyzing a feature distance according to the split image; when the feature distance is greater than a preset initial margin, calculating a difference between the preset initial margin and the feature distance, and defining the difference as a correction step length; and the machining allowance is determined through the correction step length and a preset initial allowance, and the machining allowance is defined as the initial allowance. The quenching device has the effects that the quenching effective depth and mechanical performance of the part are improved, and the situation that the machining allowance is inaccurate is reduced.

Description

Technical Field

[0001] This invention relates to the field of metal nitriding treatment, and in particular to a method and system for determining the quenching machining allowance of 42CrMo steel nitrided parts. Background Technology

[0002] Machining allowance refers to the thickness (or dimensional difference) of material to be removed during the machining process of a part, either between operations or on the blank, in order to achieve the dimensions, shape, and surface quality required by the design. Essentially, it compensates for errors during machining to ensure that the final part conforms to the drawing requirements.

[0003] 42CrMo alloy steel parts are commonly made using a combination of integral quenching (tempering) and gas nitriding. Integral quenching (tempering) is used to enhance the overall strength and toughness of the parts, while nitriding is used to significantly improve surface hardness and wear resistance, and to make the parts corrosion resistant.

[0004] The standard quenching process is as follows: After the parts are heated in the furnace and held at that temperature, they are transported from the furnace to the quenching tank using a crane or transport vehicle for quenching. After quenching, they are then transported to the tempering furnace for tempering. Before entering the quenching tank, most parts undergo natural air cooling during the transport process from the heating furnace (such as a pit furnace or bogie hearth furnace) to the quenching tank.

[0005] During this process, the surface and near-surface layer of the 42CrMo part cool down first. After cooling in the air, ferrite and other structures precipitate out. This will cause quality risks such as easy peeling of the nitrided layer in the subsequent gas nitriding process. Therefore, conventional methods remove the surface and near-surface layer as a machining allowance to reduce the presence of ferrite microstructure on the surface of the part before gas nitriding.

[0006] When quenching new structural parts or parts with complex shapes, there is no experience to refer to regarding the machining allowance in the near-surface area. Often, it is necessary to increase the machining allowance to ensure the complete removal of the near-surface ferrite structure. Excessive machining allowance can easily lead to waste of raw materials and ineffective machining work, and also cause the quenched martensite microstructure to be wasted, affecting the effective quenching depth and mechanical properties of large parts. Summary of the Invention

[0007] In order to improve the effective quenching depth and mechanical properties of parts and reduce the inaccuracy of machining allowance, this invention provides a method and system for determining the quenching machining allowance of 42CrMo steel nitrided parts.

[0008] In a first aspect, the present invention provides a method for determining the quenching machining allowance of 42CrMo steel nitrided parts, employing the following technical solution: A method for determining the quenching machining allowance of 42CrMo steel nitrided parts includes: Acquire cross-sectional images of the part's cut surface; Analyze feature distances based on the dissected image; When the feature distance is greater than the preset initial margin, the difference between the preset initial margin and the feature distance is calculated and defined as the correction step size; The machining allowance is determined by the correction step size and the preset initial allowance, and the machining allowance is defined as the initial allowance.

[0009] By adopting the above technical solution, a sample of the part is made before the nitriding process, and the sample is cut open to observe the distribution of the metallographic structure inside the part. In this way, an appropriate machining allowance is selected according to the distribution of the metallographic structure, thereby reducing the inaccuracy of the machining allowance and improving the effective quenching depth and mechanical properties of the part.

[0010] Optional, also includes: Acquire sample signals; The part contour is retrieved based on the sample signal; Determine the dissection path based on the outline of the part; Cut the parts according to the described anatomical path.

[0011] By adopting the above technical solution, the metallographic structure to be observed is different for parts of different shapes. When the surface of the part is flat, it is necessary to observe the distribution of metallographic structure in the vertical direction of the surface. When the surface of the part is curved, it is necessary to observe the distribution of metallographic structure in the normal direction of the curved surface. By selecting an appropriate cutting line according to the contour of the part, a cross section that can fully reflect the distribution of metallographic structure inside the part can be obtained.

[0012] Optionally, the method for determining the feature distance includes: Select the magnification factor based on the cut image; A magnified image is generated based on the magnification and the cut-out image; Ferrite features were identified from the magnified image; The characteristic distance is determined based on the ferrite characteristics.

[0013] By adopting the above technical solution, the metallographic structure in the sample after quenching is distributed in layers. The image of the sample cross section is magnified and the ferrite structure is observed from the sample surface to the inside until no ferrite structure is observed. The distance from this point to the sample surface is defined as the characteristic distance.

[0014] Optionally, a temperature recognition method may also be included, the temperature recognition method comprising: Calculate the heat dissipation based on the preset quenching temperature and transfer time; The heat dissipation temperature is determined by the heat dissipation, and the three-dimensional model of the part is retrieved. The center of the part is located based on the three-dimensional model; Calculate the contour distance between the center of the part and the three-dimensional model; The heat transfer is calculated by combining the contour distance, heat dissipation temperature, preset quenching temperature and transfer time; The internal temperature is determined based on the conducted heat and dissipated heat. The processing allowance is updated based on the internal temperature and the preset precipitation temperature.

[0015] By adopting the above technical solution, when the part is large in size or it is difficult to obtain a physical sample, the temperature value of each point inside the part after it is cooled by contact with air can be calculated through numerical simulation. This allows the range of ferrite structure that precipitates inside the part due to the low temperature to be determined, and the machining allowance can be corrected according to the range of ferrite structure, thereby improving the accuracy of the machining allowance.

[0016] Optionally, the temperature recognition method further includes: When the machining allowance is greater than the preset actual allowance, the heat loss volume is calculated based on the part contour and the preset actual allowance; The heat loss is calculated by combining the heat loss volume, the preset precipitation temperature, and the quenching temperature; The transportation time is determined by the aforementioned heat loss. Transportation suggestions are generated and displayed based on the stated transportation time.

[0017] By adopting the above technical solution, when the reserved machining allowance is too small, the ferrite structure is easy to spread to the part body, which will reduce the mechanical properties of the part. At this time, the maximum time that the part can be in contact with air is calculated according to the upper limit of the reserved machining allowance, so as to make transportation suggestions to reduce the situation where the time of contact between the part and the air exceeds the maximum time, resulting in an increase in the ferrite structure.

[0018] Optionally, the method for determining the transit time includes: Calculate the thickness of the part based on the three-dimensional model; The precooling time is determined based on the thickness of the part. The transfer time is determined by combining the pre-cooling time and the preset transportation time.

[0019] By adopting the above technical solution, the pre-cooling time required for the part is estimated from the three-dimensional model of the part, and then compared with the time required to transport the part. The larger of the two is then taken as the actual contact time between the part and the air, thereby improving the accuracy of the calculated part temperature.

[0020] Secondly, this application provides a system for determining the quenching machining allowance of 42CrMo steel nitrided parts, adopting the following technical solution: A system for determining the quenching machining allowance of 42CrMo steel nitrided parts includes: The acquisition module is used to acquire cross-sectional images and sample signals; The memory is used to store the program for determining the quenching machining allowance of any of the above-mentioned methods for nitriding 42CrMo steel parts. The processor is the unit of memory that allows programs to be loaded and executed by the processor.

[0021] By adopting the above technical solution, a sample of the part is made before the nitriding process, and the sample is cut open to observe the distribution of the metallographic structure inside the part. In this way, an appropriate machining allowance is selected according to the distribution of the metallographic structure, thereby reducing the inaccuracy of the machining allowance and improving the effective quenching depth and mechanical properties of the part.

[0022] In summary, this application includes at least one of the following beneficial technical effects: Before performing the nitriding process, a sample of the part is made and cut open to observe the distribution of the metallographic structure inside the part. In this way, an appropriate machining allowance is selected according to the distribution of the metallographic structure, thereby reducing the inaccuracy of the machining allowance and improving the effective quenching depth and mechanical properties of the part. The location of the metallographic structure to be observed varies depending on the shape of the part. When the surface of the part is flat, it is necessary to observe the distribution of the metallographic structure in the vertical direction of the surface. When the surface of the part is curved, it is necessary to observe the distribution of the metallographic structure in the normal direction of the curved surface. Select an appropriate cutting line according to the outline of the part to obtain a cross section that can fully reflect the distribution of the metallographic structure inside the part. After quenching, the metallographic structure inside the sample is distributed in layers. The image of the sample cross section is magnified and the ferrite structure is observed from the sample surface to the inside until no ferrite structure is observed. The distance from this point to the sample surface is defined as the characteristic distance. Attached Figure Description

[0023] Figure 1 This is a flowchart illustrating a method for determining the quenching machining allowance of nitrided 42CrMo steel parts. Figure 2 This is a flowchart of the method for determining feature distance; Figure 3 This is a flowchart of the temperature recognition method. Detailed Implementation

[0024] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the invention.

[0025] Reference Figure 1A method for determining the quenching machining allowance of 42CrMo steel nitrided parts, comprising: Step 100: Acquire the cross-sectional image of the part.

[0026] A cross-sectional image refers to a picture of the cut surface of a part sample. Cross-sectional images can be captured by a fixed camera. The method of capturing cross-sectional images is selected by the staff according to the actual situation, and will not be elaborated here.

[0027] Step 101: Analyze the feature distance based on the cut-out image.

[0028] Characteristic distance refers to the distance from the surface of a part to the point where no ferrite precipitation begins. According to the standard quenching and cooling process, after overall quenching on site, the metallographic structure of the sample from the surface to the interior consists of decarburized layer, ferrite, martensite, bainite, pearlite, etc. If a protective atmosphere is applied during quenching, there will be no decarburized layer on the outer surface. The characteristic distance is the distance from the boundary between ferrite and martensite to the surface of the part. The characteristic distance can be determined by manually observing the metallographic structure distribution on the cross-section of the part sample under a microscope. The method for determining the characteristic distance is selected by the staff according to the actual situation and will not be elaborated here.

[0029] Depending on the shape of the part, the feature distance is generally multiple values. For example, the allowance for a round bar has two values: the outer diameter and the end face. The allowance for a square block has three values: the length, the width, and the height.

[0030] Step 102: When the feature distance is greater than the preset initial margin, calculate the difference between the preset initial margin and the feature distance, and define it as the correction step size.

[0031] Initial allowance refers to the pre-set machining allowance value, which can be pre-set by the operator and will not be elaborated here. If the feature distance is greater than the initial allowance, it means that the ferrite structure cannot be completely removed when cutting the part according to the dehumidification allowance. The correction step size refers to the distance value used to adjust the machining allowance. Generally, the difference between the feature distance and the initial allowance is used as the correction step size.

[0032] When the feature distances are all less than the initial allowance, it means that the machining allowance is relatively accurate. When there are feature distances greater than the initial allowance, the sample is made repeatedly until the feature distances are all less than the initial allowance.

[0033] Step 103: Determine the machining allowance using the corrected step size and the preset initial allowance, and define the machining allowance as the initial allowance.

[0034] Machining allowance refers to the depth of cut required to completely remove the ferrite structure precipitated in the part. It is obtained by repeating the above steps until the feature distance is no greater than the initial allowance. Generally, the difference between the initial allowance and the correction step size is calculated as the machining allowance. The method for determining the machining allowance is selected by the operator according to the actual situation, and will not be elaborated here.

[0035] In practice, for large parts, a correction step of 0-3mm is considered to be a precise and waste-free quenching allowance; for small, precision or expensive parts, a correction step of 0-1mm is considered to be a precise and waste-free quenching allowance. When the correction step is within the corresponding range, the corresponding machining allowance can be calculated directly using the correction step.

[0036] Before performing the nitriding process, a sample of the part is made and cut open to observe the distribution of the metallographic structure inside the part. Based on the distribution of the metallographic structure, an appropriate machining allowance is selected, thereby reducing the inaccuracy of the machining allowance and improving the effective quenching depth and mechanical properties of the part.

[0037] A method for determining the quenching machining allowance of 42CrMo steel nitrided parts further includes: Step 104: Acquire sample signals.

[0038] The sample signal refers to the signal triggered after the sample is completed. The sample signal is selected by the staff according to the actual situation, and will not be elaborated here.

[0039] Among them, the sample part refers to the part that has been cut according to the initial allowance after quenching and is ready for further nitriding.

[0040] Step 105: Retrieve the part contour based on the sample signal.

[0041] Part profile refers to the shape and size information of a part sample. The part shape and size are divided into two types: the gas nitrided finished product profile state and the profile state including the initial allowance. The method for retrieving the part profile is selected by the staff according to the actual situation, and will not be elaborated here.

[0042] Step 106: Determine the dissection path based on the outline of the part.

[0043] The dissection path refers to the route for cutting a part sample, that is, the line segment formed by the intersection of the vertical straight line of the planar part and the normal straight line of the curved part on the surface of the part. The method for determining the dissection path is selected by the staff according to the actual situation, and will not be elaborated here.

[0044] Step 107: Cut the part according to the described anatomical path.

[0045] The location of the metallographic structure to be observed differs depending on the shape of the part. When the surface of the part is flat, it is necessary to observe the distribution of the metallographic structure in the vertical direction of the surface. When the surface of the part is curved, it is necessary to observe the distribution of the metallographic structure in the normal direction of the curved surface. By selecting an appropriate cutting line according to the contour of the part, a cross-section that can fully reflect the distribution of the metallographic structure inside the part can be obtained.

[0046] Reference Figure 2 Methods for determining feature distance include: Step 108: Select the magnification based on the cut-out image.

[0047] Magnification refers to the magnification of a cross-sectional image to facilitate observation of the distribution of ferrite structure. Generally, a magnification of 400 to 500 is used. The magnification can be selected by the staff according to the actual situation, which will not be elaborated here.

[0048] Step 109: Generate a magnified image based on the magnification and the cut-out image.

[0049] An enlarged image is an image that has been magnified according to the magnification factor of the cut-out image. The method for generating an enlarged image is common knowledge to those in the field and will not be described in detail here.

[0050] Step 110: Identify ferrite features from the magnified image.

[0051] Ferrite characteristics refer to the ferrite structure on the cross-section of a part. Ferrite characteristics can be determined by image recognition technology. The methods for identifying ferrite characteristics are common knowledge in the field and will not be elaborated here.

[0052] Step 111: Determine the feature distance based on the ferrite characteristics.

[0053] After quenching, the metallographic structure inside the sample is distributed in layers. The image of the sample cross section is magnified and the ferrite structure is observed from the sample surface to the inside until no ferrite structure is observed. The distance from this point to the sample surface is defined as the characteristic distance.

[0054] Reference Figure 3 Temperature recognition methods include: Step 200: Calculate the heat dissipation based on the preset quenching temperature and transfer time.

[0055] Quenching temperature refers to the temperature value required to quench a part, that is, the surface temperature of the part when it is taken out of the furnace after quenching and holding at the same temperature. Transfer time refers to the time that the part is in contact with air during the process of being transferred to the quenching tank after quenching. Both quenching temperature and transfer time can be preset by the staff, and will not be elaborated here.

[0056] Heat dissipation refers to the amount of heat lost by a part during its transfer to the quenching tank after quenching and contact with the air. Heat dissipation can be calculated using the quenching temperature, room temperature, and heat transfer coefficient. Room temperature refers to the air temperature inside the workshop where the part is processed, and heat transfer coefficient is a value used to show the heat exchange between the part and the air. Both room temperature and heat transfer coefficient can be pre-input by the staff, and will not be elaborated here.

[0057] Since the machining allowance of parts usually does not change with the season, but the higher the room temperature, the less easily the parts can be cooled, the smaller the machining allowance can obviously be. Therefore, the heat transfer coefficient corresponding to the average minimum temperature in winter is generally selected to ensure that the calculated machining allowance meets the requirements of any season throughout the year.

[0058] Step 201: Determine the heat dissipation temperature based on the heat dissipation and retrieve the three-dimensional model of the part.

[0059] Heat dissipation temperature refers to the temperature value of the outer surface of a part after heat loss. The method for determining heat dissipation temperature is common knowledge among those skilled in the art and will not be elaborated here. A three-dimensional model refers to the three-dimensional data of the part. The three-dimensional model can be pre-input by staff and will not be elaborated here.

[0060] Step 202: Locate the center of the part based on the three-dimensional model.

[0061] The center of a part refers to the location of its center of mass, that is, the location of its center of gravity. The method for determining the center of a part is common knowledge to those in the field and will not be elaborated here.

[0062] Step 203: Calculate the contour distance between the center of the part and the three-dimensional model.

[0063] Contour distance refers to the distance from each point on the surface of a part to the center of the part. The method for determining contour distance is common knowledge to those in the field and will not be elaborated here.

[0064] Step 204: Calculate the heat conduction by combining the contour distance, heat dissipation temperature, preset quenching temperature and transfer time.

[0065] Conductive heat refers to the amount of heat conducted from the center of a part to its surface. It can be calculated from the thermal conductivity of the part. Thermal conductivity is a value used to demonstrate the part's ability to conduct temperature. The thermal conductivity is related to the part's temperature. The thermal conductivity can be pre-quenched and entered by the staff to correspond to the quenching temperature. The calculation method for conductive heat is common knowledge in the field and will not be elaborated here.

[0066] Step 205: Determine the internal temperature based on the conducted heat and dissipated heat.

[0067] Internal temperature refers to the temperature value at various points on a component. The temperature value at various points on the surface of the component can be calculated from the heat conducted and the heat dissipated. Then, the internal temperature can be calculated from the characteristic that the temperature of the component is uniformly distributed from the surface to the center of the component. The calculation method of internal temperature is common knowledge to those in the field and will not be elaborated here.

[0068] Step 206: Update the processing allowance based on the internal temperature and the preset precipitation temperature.

[0069] The precipitation temperature refers to the critical precipitation temperature of ferrite. The precipitation temperature is related to the constituent materials of the part. The staff can look up and input the precipitation temperature corresponding to the constituent materials of the part in advance, which will not be elaborated here.

[0070] When the internal temperature is higher than the precipitation temperature, it means that ferrite is unlikely to precipitate in that area. When the internal temperature is not higher than the precipitation temperature, it means that ferrite is likely to precipitate in that area. Based on the internal temperature and precipitation temperature, the range within the part where ferrite is likely to precipitate is selected. Then, a feature distance is extracted based on the range of ferrite, and a correction step size is calculated from the feature distance. When the part is large or it is difficult to obtain a physical sample, the temperature value of each point inside the part after it is cooled by contact with air can be calculated through numerical simulation. This allows us to determine the range of ferrite precipitation inside the part due to the low temperature, and then adjust the machining allowance according to the range of ferrite precipitation to improve the accuracy of the machining allowance.

[0071] Temperature identification methods also include: Step 207: When the machining allowance is greater than the preset actual allowance, calculate the heat loss volume based on the part contour and the preset actual allowance.

[0072] Actual allowance refers to the depth of metal material that is pre-allocated during part manufacturing to allow for cutting by the cutting tool, in order to reduce damage to the part when removing machining allowance. Actual allowance can be entered in advance by the operator and will not be elaborated here. If the machining allowance is greater than the actual allowance, it means that removing ferrite according to the machining allowance is likely to damage the part body, resulting in deformation of the part after removal. Temperature loss volume refers to the total volume of metal material that can be removed, that is, the volume of metal material included in the actual allowance. The method for determining temperature loss volume is common knowledge in the field and will not be elaborated here.

[0073] Step 208: Calculate the heat loss by combining the heat loss volume, the preset precipitation temperature and the quenching temperature.

[0074] Heat loss refers to the maximum amount of heat that a part can lose when the ferrite structure does not spread to the part body. That is, the heat loss of the part when the edge temperature of the part body is exactly equal to the precipitation temperature. The edge of the part body refers to the actual margin of the part. The calculation method of heat loss is common knowledge to those in the art and will not be elaborated here.

[0075] Step 209: Determine the transportation time based on the heat loss.

[0076] The transport time refers to the maximum time that a part can be in contact with air without the ferrite structure spreading to the part body. That is, the transport time when the difference between the heat dissipation and the heat conduction is exactly equal to the heat loss. The method for calculating the transport time can refer to steps 200 and 204 above.

[0077] Step 210: Generate and display transportation suggestions based on the transportation time.

[0078] Transportation recommendations are suggestions to ensure that the transfer time of parts does not exceed the transportation time. Generally, the lower limit of the speed during transfer is used as the transportation recommendation. The lower limit of the speed can be calculated by dividing the transfer distance by the transportation time. The transfer distance refers to the distance of the part after quenching and transfer to the quenching tank. The transfer distance can be preset by the staff. The method of generating transportation recommendations is common knowledge in the field and will not be elaborated here.

[0079] When the reserved machining allowance is too small, the ferrite structure is prone to spread to the part body, which will reduce the mechanical properties of the part. At this time, the maximum time that the part can be exposed to air is calculated according to the upper limit of the reserved machining allowance, and then transportation suggestions are made to reduce the situation where the part is exposed to air for a longer time than the maximum time, which will lead to an increase in the ferrite structure.

[0080] Methods for determining transit time include: Step 211: Calculate the thickness of the part based on the three-dimensional model.

[0081] Part thickness refers to the maximum thickness value of a part. The calculation method for part thickness is common knowledge to those in the field and will not be elaborated here.

[0082] Step 212: Determine the pre-cooling time based on the thickness of the part.

[0083] Pre-cooling time refers to the air cooling time from when the part is taken out of the furnace to when it is immersed in the cooling tank, as specified by the process. In order to reduce quenching stress and reduce the temperature difference between the inside and outside of the part, the part generally needs to be left to stand for a certain period of time before being placed in the cooling tank to wait for the part temperature to drop. The pre-cooling time corresponding to the part thickness can be found from the pre-cooling relationship table. The pre-cooling relationship table is a data table that records different part thicknesses and their corresponding pre-cooling times.

[0084] Step 213: Determine the transfer time by combining the pre-cooling time and the preset transportation time.

[0085] Transportation time refers to the time it takes for parts to be transferred from the furnace after quenching and heat preservation to the cooling tank. The transportation time can be preset by the staff, and will not be elaborated here.

[0086] The precooling time required for a part is estimated by using a 3D model of the part, and then compared with the time required to transport the part. The larger of the two times is then taken as the actual contact time between the part and the air, thereby improving the accuracy of the calculated part temperature.

[0087] Based on the same inventive concept, embodiments of the present invention provide a system for determining the quenching machining allowance of 42CrMo steel nitrided parts, comprising: The acquisition module is used to acquire cross-sectional images and sample signals; The memory is used to store the program for determining the quenching machining allowance of any of the above-mentioned methods for nitriding 42CrMo steel parts. The processor is the unit of memory that allows programs to be loaded and executed by the processor.

[0088] Those skilled in the art will clearly understand that, for the sake of convenience and brevity, the above-described division of functional modules is used as an example. In practical applications, the above functions can be assigned to different functional modules as needed, that is, the internal structure of the device can be divided into different functional modules to complete all or part of the functions described above. The specific working process of the system, device, and unit described above can be referred to the corresponding process in the foregoing method embodiments, and will not be repeated here.

[0089] The above description is merely a preferred embodiment of the present invention. The scope of protection of the present invention is not limited to the above embodiments. All technical solutions falling within the scope of the present invention's concept are within the scope of protection of the present invention. It should be noted that for those skilled in the art, any improvements and modifications made without departing from the principles of the present invention should also be considered within the scope of protection of the present invention.

Claims

1. A method for determining the quenching machining allowance of 42CrMo steel nitrided parts, characterized in that, include: Acquire cross-sectional images of the part's cut surface; Analyze feature distances based on the dissected image; When the feature distance is greater than the preset initial margin, the difference between the preset initial margin and the feature distance is calculated and defined as the correction step size; The machining allowance is determined by the correction step size and the preset initial allowance, and the machining allowance is defined as the initial allowance.

2. The method for determining the quenching machining allowance of 42CrMo steel nitrided parts according to claim 1, characterized in that, Also includes: Acquire sample signals; The part contour is retrieved based on the sample signal; Determine the dissection path based on the outline of the part; Cut the parts according to the described anatomical path.

3. The method for determining the quenching machining allowance of 42CrMo steel nitrided parts according to claim 1, characterized in that, The method for determining the feature distance includes: Select the magnification factor based on the cut image; A magnified image is generated based on the magnification and the cut-out image; Ferrite features were identified from the magnified image; The characteristic distance is determined based on the ferrite characteristics.

4. The method for determining the quenching machining allowance of 42CrMo steel nitrided parts according to claim 1, characterized in that, It also includes a temperature recognition method, which includes: Calculate the heat dissipation based on the preset quenching temperature and transfer time; The heat dissipation temperature is determined by the heat dissipation, and the three-dimensional model of the part is retrieved. The center of the part is located based on the three-dimensional model; Calculate the contour distance between the center of the part and the three-dimensional model; The heat transfer is calculated by combining the contour distance, heat dissipation temperature, preset quenching temperature and transfer time; The internal temperature is determined based on the conducted heat and dissipated heat. The processing allowance is updated based on the internal temperature and the preset precipitation temperature.

5. The method for determining the quenching machining allowance of 42CrMo steel nitrided parts according to claim 4, characterized in that, The temperature identification method further includes: When the machining allowance is greater than the preset actual allowance, the heat loss volume is calculated based on the part contour and the preset actual allowance; The heat loss is calculated by combining the heat loss volume, the preset precipitation temperature, and the quenching temperature; The transportation time is determined by the aforementioned heat loss. Transportation suggestions are generated and displayed based on the stated transportation time.

6. The method for determining the quenching machining allowance of 42CrMo steel nitrided parts according to claim 4, characterized in that, The method for determining the transit time includes: Calculate the thickness of the part based on the three-dimensional model; The precooling time is determined based on the thickness of the part. The transfer time is determined by combining the pre-cooling time and the preset transportation time.

7. A system for determining the quenching machining allowance of 42CrMo steel nitrided parts, characterized in that, include: The acquisition module is used to acquire cross-sectional images and sample signals; A memory for storing a program for determining the quenching machining allowance of 42CrMo steel nitrided parts as described in any one of claims 1 to 6; The processor is the unit of memory that allows programs to be loaded and executed by the processor.

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